This week I've been working on the piano hinges that are riveted to the sides and bottom of the fuselage at the firewall. I discovered that I had made a big foul-up when I drilled the fuselage skins to the firewall. I had simply marked a line on the centre of the firewall flange, just like I did on all the other bulkheads. The result was that the edge of the firewall flange stuck out past the forward edge of the fuselage skins. I thought this would all be covered up by the cowling, but I didn't realize that the cowling, which is thicker than the fuselage skins, simply butts up against the fuselage skins, so the firewall flange must be flush with the edge of the fuselage skins, or it will interfere with the cowling. The firewall can't be removed now, so I was stuck with a tricky and tedious task of filing down the stainless steel firewall flange. At first it seemed like an impossible task, but I finally made progress by using a good quality file, a cutting lubricant (Boelube) and heavy pressure on the file. Not a fun job.

After the firewall edges were trimmed, I dimpled the holes, dimpled the hinges, riveted them in place, then fabricated a means to retain the hinge pins in place.